Apparatus for aquaculture

ABSTRACT

An apparatus for aquaculture, in particular for rearing water-dwelling fry, which is intended to be placed preferably in flowing water or water with some wave formation, is kept floating with the aid of floating elements, and consists of a breeding space formed by two end walls, two side walls, and a bottom plate, where the side walls have a number of openings. A flow-intensifying member is arranged in the upper edge of the breeding space. The size of the openings is adjustable.

TECHNICAL FIELD

The present invention relates to an apparatus for aquaculture. In thisconnection, aquaculture is to be understood as breeding of fish, fishfry, crustaceans and molluscs. In particular, the invention relates toan apparatus for rearing fish fry from the free-swimming fry stage afteregg hatching until the young-fish stage has been reached, although theapparatus is also suitable as hatchery equipment for species withattached spawn and for keeping e.g. mother fish.

STATE OF THE ART

Rearing water-dwelling fry and fish has increased in recent years andbecome all the more important both as a source of income and for thecontinued existence of many species of fish in places where theirnatural reproduction grounds have been destroyed or made inaccessible,or where the risk of genetic impoverishment exists. For this reason,many proposals have been made in order to facilitate the rearing of fryand fish where their growth environment can be controlled and they canbe protected from external dangers. The majority of these are differenttypes of breeding spaces which are placed in surrounding water and whichprovide protection for the fry during their growth.

Important factors for the growth environment are the water circulationand thus the oxygenation of the water and the hygiene in the breedingspaces. GB 2 026 823 describes, for example, a breeding space whichfloats on the water and in which the water circulation is brought aboutby means of a pump which pumps water into the space and an adjustableoutlet. The pump capacity and the outlet opening are adjusted so that ahigher water level and thus a higher pressure are obtained in the waterin the space, which leads to a circulation of the water in the space. GB1110 020 describes a breeding space which is lowered into the water,with a pump system which sucks water from the bottom of the space andinlet openings in the upper edge of the side walls of the space in orderto bring about a water circulation. The disadvantages with both systemsare that for one thing they require pump arrangements with accompanyingpower requirements, and that adjustment of the water circulation fordifferent conditions cannot be carried out satisfactorily and thatcleaning the breeding spaces is relatively complicated. All in all, thismeans that an optimum breeding environment is difficult to achieve.

DISCLOSURE OF THE INVENTION

The aim of the present invention is to remedy the above disadvantages ina manner which, without pump arrangements, can ensure good watercirculation with the aid of a number of adjustment possibilities inorder to achieve an optimum breeding environment for the water-dwellingfry in a simple and effective manner. An apparatus is thus proposedwhich comprises a breeding space which is placed in a suitablewatercourse, preferably flowing water such as brook mouths, straits,rivers and open water with some wave formation, and which is keptfloating with the aid of floating elements.

The breeding space is defined by two end walls, two side walls and abottom which slopes from one end wall to the other and in which the sidewalls have a number of openings, characterized in that aflow-intensifying member is arranged in the upper edge of the breedingspace and in that the size of the openings is adjustable. Moreover, thebottom plate has openable sections in its upper and lower pan, theslot-shaped opening of the upper section being directed in the samedirection as the flow-intensifying member and a flow being broughtabout, via an adjusting plate which conducts a flow below the breedingspace, along the bottom plate which moves food waste and excrement tothe section in the lower pan so that this can easily be removed.

The flow-intensifying member is preferably fixed in an articulatedmanner on the breeding space so that its outer end can be adjusted inthe vertical direction and that the breeding space also can be adjustedin the vertical direction in relation to the floating elements.

PREFERRED EMBODIMENT

The apparatus according to the invention will be described in detailbelow in association with a preferred embodiment and with reference tothe attached drawings, in which

FIG. 1 shows a view in perspective of the apparatus for a preferredembodiment of the invention,

FIG. 2 shows a side view of the arrangement in FIG. 1, and

FIG. 3 shows a view from above of the arrangement in FIG. 1.

The apparatus for rearing water-dwelling fry according to the inventionwhich is shown in FIGS. 1-3 comprises a breeding space 1 delimited bytwo end walls 2, 3, two side walls 4, 5 and a bottom plate 6. The wallsand the bottom are preferably made from stainless sheet metal, forexample SIS 2333 or SIS 2343, but can also be made from any othersuitable material such as, for example, aluminium or plastic. The bottomplate 6 is preferably arranged so that it slopes downwards from one endwall 2 to the other end wall 3. At the end wall 3, the bottom plate 6 isdesigned with a section 7 which is fixed in an articulated manner on thebottom plate 6 and which is manoeuvred with a manoeuvring member 8 inorder, in case of need, to create an opening in the lower end of thebottom plate 6.

At the transition between the end wall 2 and the bottom plate 6 and at adistance from the latter, there is an adjusting plate 21 which can bepushed out and can be set in various angular positions. A lower positionis designated 21'. The adjusting plate 21 is designed so that its outerpart which extends in front of the end wall 2 is angled obliquelyupwards while its inner part which is situated below the bottom plate 6is parallel to the upper edge of the breeding space 1 and is arranged sothat it can be pushed parallel thereto in order to increase or reducethe distance between the outer angled pan of the adjusting plate 21 andthe transition between the end wall 2 and the bottom plate 6.

At the end wall 2, the bottom plate 6 is designed with a section 10which is also fixed in an articulated manner on the bottom plate 6 inorder to create an adjustable slot-shaped opening for intake of flowingwater which is conducted down below the breeding space by virtue of theadjusting plate 21 which can be pushed out. The slot is adjusted with amanoeuvring member 10.

The side walls 4, 5 are provided with a number of openings 11 placed inrows along essentially the entire length of the side walls 4, 5, therows with openings 11 ending approximately where the end wall 2 mergeswith the bottom plate 6. These openings 11 can be circular, oval ordesigned as short slits or in another suitable manner and made bypunching, drilling or the like. The size of the openings can be adjustedwith a perforated sliding plate 12, 13 with corresponding openingconfiguration which lies close alongside the inside of the side walls 4,5.

The walls 2-5 and the bottom 6 form a case or box which is open upwardsand which forms the breeding space 1. Arranged around this case is asupport frame 14 which is connected to the case via preferably fourlevel-adjusting members 15, one in each comer of the case. Along boththe side walls 4, 5 of the case, floating elements 16, in the form of,for example, plastic pipes which are filled with Frigolit, are fixed tothe support frame.

In the upper edge of one end wall 2, that is to say the wall which isclosest to the openable section 10, a flow-intensifying member 17, whichnarrows towards the end which is fixed in the wall 2, is mounted in anarticulatable manner. The flow-intensifying member 17 is preferably oftrough-shaped design but can also have another design. In the upperedge, a box 9 consisting of grating material can be placed forcollecting creatures and rubbish and in order to prevent this beingflushed into the breeding space 1.

The outer end of the flow-intensifying member 17 can be adjusted in thevertical direction with the aid of, for example, support struts 18 onboth sides thereof, or in another suitable manner.

Functioning is as follows. The arrangement for rearing water-dwellingfry is placed in a suitable watercourse, either one which is flowing orin which there is some wave formation. The arrangement floats on thewater by virtue of the floating elements 16 and, with the aid of thelevel-adjusting members 15, the water level in the breeding space can beadjusted. When the breeding space 1 is in its highest position, it ispossible to carry out e.g. sorting, catching or treatment of the fish orfry and the bottom can be cleaned. In the lowered position, thearrangement is so stable that a person can stand on the floatingelements 16 without a problem.

In order to obtain the best functioning, the arrangement is placed inthe water in such a manner that the end wall 2 with thewave-intensifying and flow-intensifying member 17 is directed towardsthe direction of the flow or waves. The breeding space 1 is thenadjusted vertically with the aid of the level-adjusting members 15 andthe flow-intensifying member 17 is angled with the aid of the supportstruts 18 depending upon the flow and wave conditions so that itconducts a given amount of water into the breeding space via the member17 and brings about refilling with water and a flow and thus oxygenationof the water in the space which then flows out through the openings 11in the side walls 4, 5. These openings are adjusted with the slidingplates 12, 13 for the prevailing conditions in order to achieve asomewhat higher water level in the breeding space 1 and thus provide fora good throughflow. Desludging of the openings 11 can also be carriedout easily by guiding the sliding plates 12, 13 to and fro. By adjustingthe size of the openings 11, the arrangement can also be adapted todifferent fry sizes.

The sliding plate 21 is set so that a suitable quantity of the downwardflow is directed in below the breeding space 1. A part of this flow istaken into the breeding space 1 via the slot-shaped opening defined bythe section 10 and acts as a cleaning flow along the sloping bottomplate 6, that is to say transports excrement and food residues downtowards the lower end of the bottom 6 and the section 7.

On cleaning, the section 7 is opened so that food waste and excrementcan be removed simply from the breeding space 1.

All in all, these adjustment possibilities mean that an optimumthroughflow and thus a good environment for the water-dwelling fry canbe provided for entirely without aids in the form of pumps or the like.

Preferably, the apparatus is also provided with a spring-operatedautomatic feeder 19 for automatic feeding of the fry.

The arrangement can also be provided with openable protective hatches20, which are preferably transparent, in order to prevent leaves andother plant pans getting into the breeding space and to prevent gullsand other seabirds gaining access to the fry.

The arrangement according to the invention has a range of advantagescompared with o the state of the an as a result of its simple and robustconstruction and the fact that, as a result of the many adjustmentpossibilities, it makes possible very good breeding environments forwater-dwelling fry with a minimum of care and without aids which aredependent upon electric power. In watercourses without flow and waveformation, however, the arrangement can be provided with a preferablysolar-cell operated flow arrangement in order to increase the waterthroughflow.

From what is indicated, it emerges that the invention cannot beconsidered to be limited to the preferred embodiment described above andshown in the drawings but can be subject to various modifications withinthe scope of what is stated in the following patent claims.

I claim:
 1. An apparatus for aquaculture for rearing water-dwelling fry,the apparatus is adapted to be floating in flowing water or in waterhaving some wave formation, the apparatus comprising:a frame; a floatingelement attached to the frame; two opposite end walls; two opposite sidewalls placed in between the end walls and attached thereto; a bottomplate attached to the end walls and the side walls so that the endwalls, side walls and the bottom plate form a structure, the structurehaving an upper edge; a breeding space defined by the structure; aflow-intensifying member attached to the upper edge of the structure,the flow-intensifying member having solid walls; and a plurality ofopenings defined in the structure, the openings having a size that isadjustable.
 2. An apparatus according to claim 1 wherein theflow-intensifying member is movably attached to the structure and aportion of the flow-intensifying member is vertically adjustable.
 3. Anapparatus according to claim 2 wherein the flow-intensifying member hasan inflow end and an outflow end, the outflow end is more narrow thanthe inflow end and the outflow end is attached to the structure.
 4. Anapparatus according to claim 1 wherein the openings are defined in theside walls and the size of the openings is adjustable by sliding platesattached to the side walls.
 5. An apparatus according to claim 1 whereinthe structure is vertically adjustable relative to the floating element.6. An apparatus according to claim 5 wherein the floating element issecured to the frame and the frame is attached to the structure andvertically adjustable relative thereto so that when the apparatus isplaced in water, the vertical position of the structure is adjustablerelative to a water level of the water.
 7. An apparatus according toclaim 1 wherein the apparatus has a movable section in the bottom platethat is movable between an open position and a closed position, themovable section is aligned with the flow-intensifying member.
 8. Anapparatus according to claim 7 wherein the apparatus includes anadjusting plate attached to the frame and positioned below the movablesection, the adjusting plate has a front part and a lower part, thefront part is angled obliquely upwardly towards the flow-intensifyingmember and the lower part is substantially parallel to the structure. 9.An apparatus according to claim 8 wherein the front part of theadjusting plate is movable into a position that is parallel to thestructure.
 10. An apparatus according to claim 7 wherein the bottomplate has a movable portion that is movable between an open position anda closed position, the movable portion is remote from the movablesection.
 11. An apparatus according to claim 7 wherein the movablesection is slot-shaped when the movable section is in the open position.12. An apparatus according to claim 1 wherein the bottom plate slopesdownwardly from one of the end walls attached to the flow-intensifyingmember towards the opposite end wall.
 13. An apparatus according toclaim 1 wherein the apparatus has a transparent protective sheet placedon top of the structure.
 14. An apparatus for aquaculture for rearingwater-dwelling fry, the apparatus is adapted to be floating in flowingwater or in water having some wave formation, the apparatus comprising:aframe; two opposite end walls; two opposite side walls placed in betweenthe end walls and attached thereto; a bottom plate attached to the endwalls and the side walls so that the end walls, side walls and thebottom plate from a rectangular-shaped structure, the structure havingan upper edge, the bottom plate having a movable section that is movablebetween an open position and a closed position; a breeding space definedby the structure; a floating element attached to the frame, the floatingelement being vertically adjustable relative to the frame so that whenthe apparatus is placed in water, the vertical position of the structureis adjustable relative to a water level of the water, the floatingelement being aligned with the movable section of the bottom plate; aflow-intensifying member having an inflow end and an outflow end, theoutflow end being more narrow than the inflow end, the outflow beingmovably attached to the upper edge of the structure, theflow-intensifying member having a portion that is vertically adjustablerelative to the frame, the bottom plate sloping downwardly and away fromthe flow-intensifying member; a plurality of openings defined in theside walls, the openings having a size that is adjustable by slidingplates attached to the side walls; an adjusting plate attached to theframe, the adjusting plate being positioned below the movable section ofthe bottom plate, the adjusting plate having a front part and a lowerpart, the front part being angled obliquely upwardly towards theflow-intensifying member and the lower part being substantially parallelto the structure; and a transparent protective sheet placed on top ofthe structure.